Integrated circuit cards have proven useful as a storage medium that enables data processing in cashless purchases, monitoring passenger traffic, and/or charge management in accessing telephone networks.
Generally, there are two types of integrated circuit cards, each having a different signal transmission method. One type is a contact integrated circuit card that receives power and clocks from a reader/writer by use of a contact point that processes a command from the reader/writer. The second type is a contactless integrated circuit card having a coil and an integrated circuit connected to the coil, where the card communicates wirelessly with a reader/writer. A coil of the reader/writer generates a magnetic field to power the card. The coil of the contactless integrated circuit card electromagnetically couples with the coil of the reader/writer to enable bi-directional data and power transfer. The contactless integrated circuit card has no moving parts to wear out and is inexpensive to manufacture.
Inductance from the coil and capacitance of the integrated circuit combine to form a resonance circuit that enables power transmission between the contactless reader/writer and the contactless integrated circuit card. It is desirable to adjust the coil inductance and the chip capacitance to enable the efficient power and data transfer between the reader/writer and the card.
As contactless integrated circuit cards become smaller (and more popular), each card size will necessitate a different optimum inductance value and different capacitance values for the integrated circuit. Thus, these advances will demand many different chip types each having different input capacitance values.
For these and other reasons there is a need for the present invention.